In traditional cancer diagnosis, (histo-)pathological images of tissue samples are visually analysed by pathologists. Using a microscope, the pathologist inspects the tissue. As these samples contain 3D structures and the depth of field of the microscope is limited, not all parts will be in focus. By turning the focus knob, the pathologist is able to go through the tissue in the z-direction (i.e. depth direction). However, using a digital microscope, the tissue samples are automatically scanned. In case the tissue is scanned at a single depth, not all parts of the tissue can be in focus. Scanning the slides at multiple depths leads to the acquisition and storage of a significant amount of data.
US2005/0089208A1 describes a system and method for obtaining images of a microscope slide.